@travetto/asset

travetto: Asset

This module provides the framework for storing/retrieving assets. It also provides additional image functionality for on-the-fly resizing.

GraphicsMagick is used under the covers for image transformation. If the binary is not installed the framework will spin up a docker container to provide needed functionality.

The primary driver for the Asset framework is an AssetSource which needs to be implemented to provide code on how to read and write files.

Initially you need to configure the AssetSource to provide a backend for the storage and retrieval. Below we are using the Asset-Mongo as the backend, but there are others to choose from.

class AppConfig {
  @InjectableFactory()
  static getConf(): AssetMongoConfig {
    return new AssetMongoConfig();
  }
  @InjectableFactory()
  static getSource(cfg: AssetMongoConfig): AssetSource {
    return new AssetMongoSource(cfg);
  }
}

After that, both AssetService and ImageService will rely upon the AssetSource to do their work. Below you can see an example of storing and retrieving a user's profile image.
Storing of all assets goes through the AssetService, but retrieval can either be from AssetService or ImageService depending on whether or not you want to perform image optimizations on retrieval.

@Injectable()
class UserProfileService {

  constructor(
    private asset: AssetService, 
    private image: ImageService,
    private model: ModelService
  ) {}

  async saveProfileImage(userId: string, image: Asset) {
    const path = await this.asset.store(image);
    const user = await this.model.getById(User, userId);
    user.profileImage = path;
    await this.model.update(User, user);
  }

  async getProfileImage(userId:string) {
    const user = await this.model.getById(userId);
    return await this.image.getImage(user.profileImage, { w: 100, h: 100 });
  }
}

The current set of supported AssetSource implementations are:

• Asset-Mongo provides the mongodb driver for file management
• Asset-S3 provides the S3 driver for file management